staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()grafted

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/drivers/base/regmap/regmap-ram.c b/drivers/base/regmap/regmap-ram.c
new file mode 100644
index 000000000..c7356b0d8
--- /dev/null
+++ b/drivers/base/regmap/regmap-ram.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Register map access API - Memory region
+//
+// This is intended for testing only
+//
+// Copyright (c) 2023, Arm Ltd
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/swab.h>
+
+#include "internal.h"
+
+static int regmap_ram_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct regmap_ram_data *data = context;
+
+	data->vals[reg] = val;
+	data->written[reg] = true;
+
+	return 0;
+}
+
+static int regmap_ram_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct regmap_ram_data *data = context;
+
+	*val = data->vals[reg];
+	data->read[reg] = true;
+
+	return 0;
+}
+
+static void regmap_ram_free_context(void *context)
+{
+	struct regmap_ram_data *data = context;
+
+	kfree(data->vals);
+	kfree(data->read);
+	kfree(data->written);
+	kfree(data);
+}
+
+static const struct regmap_bus regmap_ram = {
+	.fast_io = true,
+	.reg_write = regmap_ram_write,
+	.reg_read = regmap_ram_read,
+	.free_context = regmap_ram_free_context,
+};
+
+struct regmap *__regmap_init_ram(struct device *dev,
+				 const struct regmap_config *config,
+				 struct regmap_ram_data *data,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name)
+{
+	struct regmap *map;
+
+	if (!config->max_register) {
+		pr_crit("No max_register specified for RAM regmap\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	data->read = kzalloc_objs(bool, config->max_register + 1);
+	if (!data->read)
+		return ERR_PTR(-ENOMEM);
+
+	data->written = kzalloc_objs(bool, config->max_register + 1);
+	if (!data->written) {
+		kfree(data->read);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	map = __regmap_init(dev, &regmap_ram, data, config,
+			    lock_key, lock_name);
+	if (IS_ERR(map)) {
+		kfree(data->read);
+		kfree(data->written);
+	}
+
+	return map;
+}
+EXPORT_SYMBOL_GPL(__regmap_init_ram);
+
+MODULE_DESCRIPTION("Register map access API - Memory region");
+MODULE_LICENSE("GPL v2");